Deflagration venting nomographs

Six-tenths factor, 47 Yearly cost indices, 47 Critical flow, safety-relief, 438 Back pressure, 440 Sonic flow, 438 Critical flow, see Sonic Cyclone separators, 259-269 Design, 260-265 Efficiency chart, 263 Hydroclones, 265-267 Pressure drop, 263, 264 Scrubber, 269 Webre design, 265 Deflagration venting nomographs,... 

Figure 7-63A. Venting nomograph for methane. Reprinteed with permission, NFPA 68-1988, Deflagration Venting, (1988) National Fire Protection Association, Quincy, MA 02269. Note This materiai is not the complete and official position of the National Fire Protection Association on the referenced subject, which is represented only by the standard in its entirety. Note from this author this statement applies to all material referenced for use that originates with the National Fire Protection Association [27].

Figure 7-63B. Venting nomograph for propane. Reprinted with permission, NFPA 68-1988, Deflagration Venting, (1988) National Fire Protection Association, Quincy, MA 02269. See note Figure 7-63A.

Interpolation of exisdng nomographs to determine deflagration vent area of different gas-air mixtures ... 

Using a nomograph requires only the vessel volume in meters, selecting the dust class. St-1, St-2 or St-3 from Table 7-28. Using Tables 7-29 or 7-30 select the Kst value determined experimentally. The reduced pressure, Pfed. (maximum pressure actually developed during a vented deflagration, termed reduced explosion pressure) must not exceed strength of vessel (see earlier discussion) and the Psut, i.e., the vent device release pressure. Note that the static activation pressure, Pjj, must be determined from experimental tests of the manufacture of relief panels such as rupture disks. 

Venting, dusts, (deflagration), nomograph, API, 514-520 Relief valves, 400 Code requirements, 415, 420 Installation, 422, 429-434 Safety-relief, 400 Relieving pressure, 411-417 Resistance coefficient, K, (flow), 71, 72 Flow coefficient, Q, 81, 83 Pipe sizing, 83, 84, 86 Sudden contraction, 80 Sudden enlargement, 80 Tables/charts, 73-76, 77, 78-80 Valves, 81... 

---